1. Technical Field
The present disclosure relates to a micro gas turbine system.
2. Description of the Related Art
Conventionally, small gas turbine systems capable of providing a low temperature heat source have been known. For example, Japanese Unexamined Patent Application Publication No. 2001-152871 discloses a small gas turbine apparatus 300 as illustrated in FIG. 7. The small gas turbine apparatus 300 includes a first rotating mechanism including a first compressor 303 and a first expansion turbine 307, and a second rotating mechanism including a second compressor 313 and a second expansion turbine 316. The second compressor 313 receives and compresses a part of air compressed by and outputted from the first compressor 303. The second expansion turbine 316 expands the air compressed by the second compressor 313. Exhaust from the second expansion turbine 316 is usable as a low temperature heat source.
As another example, International Publication No. 2011/152049 discloses a gas turbine system 500 suitable for in-vehicle use as illustrated in FIG. 8. The gas turbine system 500 includes a gas turbine apparatus 502, a cooling fluid generating apparatus 505, an air conditioning unit 506, and a heat exchanger 507. The gas turbine apparatus 502 includes a first compressor 521 and a first expansion turbine 523, which are connected to each other via a first shaft 522; a burner 526; and a regenerated heat exchanger 527. Further, the gas turbine apparatus 502 includes a generator 524 connected to the first shaft 522. The cooling fluid generating apparatus 505 includes a second compressor 551 and a second expansion turbine 553, which are connected to each other via a second shaft 552; a cooler 55; and a water separator 556. Further, the cooling fluid generating apparatus 505 includes a generator 554 connected to the second shaft 552. The cooling fluid generating apparatus 505 is provided with a carburetor 557 upstream of the cooler 555. The air conditioning unit 506 includes a mixer 562 and a blower 561.
The first compressor 521 takes in and compresses air taken from atmospheric air. High pressure air discharged from the first compressor 521 flows into the regenerated heat exchanger 527 and then flows into the burner 526. The combustion gas generated in the burner 526 flows into and expands in the first expansion turbine 523. Thereby, the pressure of the combustion gas drops down to a level around the atmospheric pressure. The combustion gas discharged from the first expansion turbine 523 flows into the regenerated heat exchanger 527. In the regenerated heat exchanger 527, the combustion gas and high pressure air before flowing into the burner 526 exchange heat. The second compressor 551 is connected to one end of an air-extraction passage 504 for extracting air (extracted air) boosted by the first compressor 521 from the gas turbine apparatus 502. The second compressor 551 receives and compresses the extracted air. High pressure air discharged from the second compressor 551 passes through the carburetor 557 and the cooler 555. In the carburetor 557, the temperature of high pressure air discharged from the second compressor 551 drops due to vaporization heat of the fuel. High pressure air flowing out from the cooler 555 flows into and expands in the second expansion turbine 553. Thereby, the pressure of the high pressure air drops down to a level around the atmospheric pressure. Cool air (cooling fluid) is generated by expansion of the air in the second expansion turbine 553. The air discharged from the second expansion turbine 553 passes through the water separator 556 and then is fed to the air conditioning unit 506. The water separator 556 separates moisture from the air discharged from the second expansion turbine 553.
Air discharged from the second expansion turbine 553 is mixed with air supplied from the blower 561 in the mixer 562 and thereby is adjusted to a desired temperature. The adjusted air is fed to the heat exchanger 507. The heat exchanger 507 causes heat exchange between the adjusted air flowing out from the mixer 562 and the combustion gas flowing out from the regenerated heat exchanger 527 mentioned above and thereby heats the adjusted air flowing out from the mixer 562 to a temperature suitable for air conditioning. Then, the air heated by the heat exchanger 507 is supplied to a cabin. However, when cooling, the air adjusted by the air conditioning unit 506 to a temperature suitable for a demanded temperature in air conditioning also may be supplied directly to the cabin without passing through the heat exchanger 507. Thus, the air discharged from the second expansion turbine 553 in the gas turbine system 500 is utilized for air conditioning in the cabin.